Tensions of Liquids and their Chemical Constitution. 91 



face tension greater than that of ethylbenzene, but less than 

 that of toluene. 



The laws which underlie these phenomena can be discovered 

 only when the data are much more numerous, although with 

 the above liquids important hints are given as to how those 

 laws will be stated. We find further that the specific gravi- 

 ties of these hydrocarbons have but little, if any, influence 

 upon their surface tensions. True, the differences of density 

 are slight, but it is seen that benzene with the greatest and 

 o-xylene with the least density have the same drop-size. And 

 again, the weights of the drops of toluene and ethylbenzene, 

 liquids of almost the same specific gravity, are widely different. 

 Guthrie's first law, as stated above, seems to be verified by 

 these facts. 



Of the few liquids heavier than water which I examined, 

 the majority have a similar constitution! These were all care- 

 fully purified and only portions boiling within a fraction of a 

 degree taken. The results of the determinations are given in 

 Table III., where Column I, gives the name and Col. II, the for- 

 mula of the liquids. The specific gravities at 0° for the most 

 part are entered in Col. Ill, and the weights of drops of water 

 in the organic liquids in Col. IY. Cols. Y and YI give the 

 weights of the drops of the liquids into water, orifices of dif- 

 ferent sizes being used. 



Table III. 



I. 



II. 



III. 



IV. 



V. 



VI. 



Nitrobenzene 



C 6 H 5 .N0 2 



1-2 



0-0518 



0-0328 





Carbon disulphide 



cs„ 



1-29 



0-06(57 



0-0384 



0-046 L 



Amyl bromide 



C B H U . Br 



1-28 



0-0666 



0-0382 



0-0460 



Ethyl bromide 



C„H 5 Br 



1-47 



0-0236 



0-0182 



0-0221 



Benzene bromide 



CX.Br 



1-517 



0-0283 



0-0237 



00280 



Chloroform 



CHC1 3 



1-52 



0-G229 



0-0278 



0-0362 



Ethylene bromide 



C 2 H 4 Br 2 



2-18 



0-0106 



0-0137 



0-0183 



Bromoform 



CHBr 



2-83 



0-0069 





0-0176 



If the numbers in Cols. Y and YI, be plotted as ordinates 

 and the corresponding densities as abscissas, the resulting curves 

 will be seen to be parallel, showing similarity, as might be ex- 

 pected, in the results obtained with different sized orifices. 



Regarding Col. II, we see that carbon disulphide and amyl 

 bromide, liquids of the same specific gravity, have the same 

 drop-size, while benzene bromide and chloroform, also liquids 

 of about the same density, have quite different drop-sizes. A 

 difference in the chemical constitution of these last two bodies 

 may explain their difference in surface tension ; we see also 

 that, although the density of nitrobenzene is less than that of 

 amyl bromide and carbon disulphide, its drop-size is not 

 greater. 



